Trelane later escaped from his parents again. The Enterprise again encountered Trelane in 2269 while investigating the disappearance of several vessels. During their second encounter, Trelane had become fascinated with the First World War. Trelane attacked the Enterprise with a space vessel made to resemble an early biplane. Kirk and the Enterprise crew were able to defeat the biplane, but Trelane then subjected several Starfleet officers to a simulation of a period German village. Kirk was again able to disrupt Trelane's power, and Trelane's nanny discovered him and took him away. (TOSvideo game: Judgment Rites)

Alternatively, the player could have Kirk talk Trelane into taking him to a simulation of a real World War I battlefield, rather than the romanticized version Trelane had created. After Kirk tries to convince Trelane that there's nothing romantic about war, Trelane loses interest in holding the Enterprise or the other ships, and allows them to leave.

Years later, Trelane appeared again. Kirk told Trelane he had no interest in any more of Trelane's war games. However, Trelane revealed he was interested in romantic conquests now, which Kirk was quite familiar with. Effectively holding the Enterprise hostage and giving Kirk a brief but first hand reminder of Gothos' deadly atmosphere, Kirk was first made to try and charm a random woman at a bar (and nearly getting killed because the woman was already taken).

Trelane also subjected Kirk to a hallucination of the Enterprise crew (in particular Spock) into trying to kill Kirk in an attempt to appease Trelane's threats.

Taking a unintended hint from Kirk, Trelane switched tactics and instead made Kirk reunited with an old flame of his, Theresa Ross, but Kirk refused to follow through purely for Trelane's amusement. Punching Trelane in the face and knocking him down, Kirk called him "a boy in a man's body."

Trelane chastised Kirk for thinking Kirk was the only one to have aged in the years since their last encounter.

Kirk having had enough of Trelane's games set the Enterprise for auto-destruct, Spock figuring the explosion would be enough to kill even Trelane. Trelane in a tantrum destroyed the part of the ship's computer responsible for the self-destruct declaring no one would destroy the Enterprise but him. Trelane revealed all he wanted was Kirk's advice and example on how to handle the ladies. Uhura then plays a part, pretending to want to give Trelane more hands on advice on the subject.

A good deal of this turned out to be delaying tactics on part of the crew, having noticed Trelane having repeatedly moved the ship when a powerful energy signature neared. The signature turns out to be a female of Trelane's species, Valedsia. Kirk was amused at Trelane's cowering at her presence. Kirk told them both to leave his ship at once, and the Valedsia was more than willing to comply with this, dragging off Trelane eagerly and happily as Trelane begged Kirk for help. McCoy found it interesting that coming from a race as advanced as them "they wanted advice on the birds and the bees." Spock noted that the more advanced the civilization, the more arrogant its youth. (TOScomic: "A Little Man-to-Man Talk")

In the 24th century, the crew of the USS Enterprise-D encountered Trelane, and finally learned that he was a member of the Q Continuum. After Trelane acquired control of the Heart of the Storm, a part of the fundamental structure of the universe, capable of granting Trelane power over the very structure of chaos itself, he began to collapse three alternate timelines together for little more than the sake of it, driving an alternate version of Jack Crusher insane by revealing that he was the only version of himself left in the multiverse, as well as dispersing Q across the universe after sealing the Q Continuum away from the rest of reality. However, Q was able to piece himself back together over the millennia thanks to a signal sent out by his future self, with the result that, when he 'caught up' with Trelane in the present, his powers were intact enough for him to protect CaptainJean-Luc Picard and some of his crew from the insanity that would have been caused by Trelane's manipulation of reality. With the aid of CommanderRiker, LieutenantWorf and an alternate version of Lieutenant CommanderNatasha Yar, Picard was able to teleport down to the planet Terminus- an artificial creation made to serve as a focus for Trelane's game- and confront Trelane in a sword-fight using a sword that was really Q's essence, Picard exploiting Trelane's overconfidence and limited practical knowledge of swordfighting to stab him in the chest, allowing Q-in-the-sword to disrupt Trelane's connection to the Heart of the Storm and disperse him into nothing, simultaneously restoring Q's powers. As he restored reality to normal, Q implied in a conversation with Picard that Trelane may have been his own illegitimate son, but his mother's high status in the Continuum meant that any relationship between her and Q would have been scandalous at best, and Picard respected Q's desire to let the matter drop. (TNGnovel: Q-Squared)

In early 2372, Trelane began playing a strange game of chess with Q, using the crews of two starships Enterprise as pawns. As each superbeing was convinced that the captain he was used to dealing with was superior (Kirk for Trelane and Picard for Q), they switched the captains' places, allowing Kirk to take command of the brand-new USS Enterprise-E on the day of its launch, while Picard had to assume command of the original Enterprise during a Klingon attack. Both captains adapted to their new situations, and were able to work together to overcome Trelane and Q. (ST - Unlimitedcomic: "An Infinite Jest")